replace line break

I am trying to use the replace() function to remove any line breaks in a string. I have tried replacing "\r\n" with an empty space (" "), but that doesn't work. Has anybody tried this before?

The reason I am trying to do this is that I want to email the contents of a multiline column via a workflow email action. Unfortunately any occurence of a linebreak within the HTML code that is emailed, is converted into a "<br/>" by the
emailing workflow action first. Very annoying! So I thought I'd use the string replace function to get rid of any linebreaks and "clean" the HTML that way.